Commit 9dee8689 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'objtool-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull objtool updates from Ingo Molnar:

 - Add support for non-rela relocations, in preparation to merge
   'recordmcount' functionality into objtool

 - Fix assumption that broke under --ffunction-sections (LTO) builds

 - Misc cleanups

* tag 'objtool-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Add support for relocations without addends
  objtool: Rename rela to reloc
  objtool: Use sh_info to find the base for .rela sections
  objtool: Do not assume order of parent/child functions
parents 9ba19ccd d832c005

tools/objtool/arch.h

+1 −1
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ bool arch_callee_saved_reg(unsigned char reg); 


unsigned long arch_jump_destination(struct instruction *insn);



unsigned long arch_dest_rela_offset(int addend);

unsigned long arch_dest_reloc_offset(int addend);



const char *arch_nop_insn(int len);

tools/objtool/arch/x86/decode.c

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ bool arch_callee_saved_reg(unsigned char reg) 
	}

}



unsigned long arch_dest_rela_offset(int addend)

unsigned long arch_dest_reloc_offset(int addend)

{

	return addend + 4;

}

tools/objtool/check.c

+101 −101
Original line number Diff line number Diff line
@@ -353,7 +353,7 @@ static struct instruction *find_last_insn(struct objtool_file *file, 
static int add_dead_ends(struct objtool_file *file)

{

	struct section *sec;

	struct rela *rela;

	struct reloc *reloc;

	struct instruction *insn;



	/*
@@ -371,24 +371,24 @@ static int add_dead_ends(struct objtool_file *file) 
	if (!sec)

		goto reachable;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}

		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (insn)

			insn = list_prev_entry(insn, list);

		else if (rela->addend == rela->sym->sec->len) {

			insn = find_last_insn(file, rela->sym->sec);

		else if (reloc->addend == reloc->sym->sec->len) {

			insn = find_last_insn(file, reloc->sym->sec);

			if (!insn) {

				WARN("can't find unreachable insn at %s+0x%x",

				     rela->sym->sec->name, rela->addend);

				     reloc->sym->sec->name, reloc->addend);

				return -1;

			}

		} else {

			WARN("can't find unreachable insn at %s+0x%x",

			     rela->sym->sec->name, rela->addend);

			     reloc->sym->sec->name, reloc->addend);

			return -1;

		}
@@ -406,24 +406,24 @@ reachable: 
	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}

		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (insn)

			insn = list_prev_entry(insn, list);

		else if (rela->addend == rela->sym->sec->len) {

			insn = find_last_insn(file, rela->sym->sec);

		else if (reloc->addend == reloc->sym->sec->len) {

			insn = find_last_insn(file, reloc->sym->sec);

			if (!insn) {

				WARN("can't find reachable insn at %s+0x%x",

				     rela->sym->sec->name, rela->addend);

				     reloc->sym->sec->name, reloc->addend);

				return -1;

			}

		} else {

			WARN("can't find reachable insn at %s+0x%x",

			     rela->sym->sec->name, rela->addend);

			     reloc->sym->sec->name, reloc->addend);

			return -1;

		}
@@ -441,26 +441,26 @@ static void add_ignores(struct objtool_file *file) 
	struct instruction *insn;

	struct section *sec;

	struct symbol *func;

	struct rela *rela;

	struct reloc *reloc;



	sec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard");

	if (!sec)

		return;



	list_for_each_entry(rela, &sec->rela_list, list) {

		switch (rela->sym->type) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		switch (reloc->sym->type) {

		case STT_FUNC:

			func = rela->sym;

			func = reloc->sym;

			break;



		case STT_SECTION:

			func = find_func_by_offset(rela->sym->sec, rela->addend);

			func = find_func_by_offset(reloc->sym->sec, reloc->addend);

			if (!func)

				continue;

			break;



		default:

			WARN("unexpected relocation symbol type in %s: %d", sec->name, rela->sym->type);

			WARN("unexpected relocation symbol type in %s: %d", sec->name, reloc->sym->type);

			continue;

		}
@@ -580,20 +580,20 @@ static void add_uaccess_safe(struct objtool_file *file) 
static int add_ignore_alternatives(struct objtool_file *file)

{

	struct section *sec;

	struct rela *rela;

	struct reloc *reloc;

	struct instruction *insn;



	sec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");

	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("bad .discard.ignore_alts entry");

			return -1;
@@ -611,7 +611,7 @@ static int add_ignore_alternatives(struct objtool_file *file) 
static int add_jump_destinations(struct objtool_file *file)

{

	struct instruction *insn;

	struct rela *rela;

	struct reloc *reloc;

	struct section *dest_sec;

	unsigned long dest_off;
@@ -622,19 +622,19 @@ static int add_jump_destinations(struct objtool_file *file) 
		if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)

			continue;



		rela = find_rela_by_dest_range(file->elf, insn->sec,

		reloc = find_reloc_by_dest_range(file->elf, insn->sec,

					       insn->offset, insn->len);

		if (!rela) {

		if (!reloc) {

			dest_sec = insn->sec;

			dest_off = arch_jump_destination(insn);

		} else if (rela->sym->type == STT_SECTION) {

			dest_sec = rela->sym->sec;

			dest_off = arch_dest_rela_offset(rela->addend);

		} else if (rela->sym->sec->idx) {

			dest_sec = rela->sym->sec;

			dest_off = rela->sym->sym.st_value +

				   arch_dest_rela_offset(rela->addend);

		} else if (strstr(rela->sym->name, "_indirect_thunk_")) {

		} else if (reloc->sym->type == STT_SECTION) {

			dest_sec = reloc->sym->sec;

			dest_off = arch_dest_reloc_offset(reloc->addend);

		} else if (reloc->sym->sec->idx) {

			dest_sec = reloc->sym->sec;

			dest_off = reloc->sym->sym.st_value +

				   arch_dest_reloc_offset(reloc->addend);

		} else if (strstr(reloc->sym->name, "_indirect_thunk_")) {

			/*

			 * Retpoline jumps are really dynamic jumps in

			 * disguise, so convert them accordingly.
@@ -648,7 +648,7 @@ static int add_jump_destinations(struct objtool_file *file) 
			continue;

		} else {

			/* external sibling call */

			insn->call_dest = rela->sym;

			insn->call_dest = reloc->sym;

			continue;

		}
@@ -724,15 +724,15 @@ static int add_call_destinations(struct objtool_file *file) 
{

	struct instruction *insn;

	unsigned long dest_off;

	struct rela *rela;

	struct reloc *reloc;



	for_each_insn(file, insn) {

		if (insn->type != INSN_CALL)

			continue;



		rela = find_rela_by_dest_range(file->elf, insn->sec,

		reloc = find_reloc_by_dest_range(file->elf, insn->sec,

					       insn->offset, insn->len);

		if (!rela) {

		if (!reloc) {

			dest_off = arch_jump_destination(insn);

			insn->call_dest = find_func_by_offset(insn->sec, dest_off);

			if (!insn->call_dest)
@@ -752,19 +752,19 @@ static int add_call_destinations(struct objtool_file *file) 
				return -1;

			}



		} else if (rela->sym->type == STT_SECTION) {

			dest_off = arch_dest_rela_offset(rela->addend);

			insn->call_dest = find_func_by_offset(rela->sym->sec,

		} else if (reloc->sym->type == STT_SECTION) {

			dest_off = arch_dest_reloc_offset(reloc->addend);

			insn->call_dest = find_func_by_offset(reloc->sym->sec,

							      dest_off);

			if (!insn->call_dest) {

				WARN_FUNC("can't find call dest symbol at %s+0x%lx",

					  insn->sec, insn->offset,

					  rela->sym->sec->name,

					  reloc->sym->sec->name,

					  dest_off);

				return -1;

			}

		} else

			insn->call_dest = rela->sym;

			insn->call_dest = reloc->sym;



		/*

		 * Many compilers cannot disable KCOV with a function attribute
@@ -773,9 +773,9 @@ static int add_call_destinations(struct objtool_file *file) 
		 */

		if (insn->sec->noinstr &&

		    !strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) {

			if (rela) {

				rela->type = R_NONE;

				elf_write_rela(file->elf, rela);

			if (reloc) {

				reloc->type = R_NONE;

				elf_write_reloc(file->elf, reloc);

			}



			elf_write_insn(file->elf, insn->sec,
@@ -890,7 +890,7 @@ static int handle_group_alt(struct objtool_file *file, 
		 */

		if ((insn->offset != special_alt->new_off ||

		    (insn->type != INSN_CALL && !is_static_jump(insn))) &&

		    find_rela_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {

		    find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {



			WARN_FUNC("unsupported relocation in alternatives section",

				  insn->sec, insn->offset);
@@ -1036,34 +1036,34 @@ out: 
}



static int add_jump_table(struct objtool_file *file, struct instruction *insn,

			    struct rela *table)

			    struct reloc *table)

{

	struct rela *rela = table;

	struct reloc *reloc = table;

	struct instruction *dest_insn;

	struct alternative *alt;

	struct symbol *pfunc = insn->func->pfunc;

	unsigned int prev_offset = 0;



	/*

	 * Each @rela is a switch table relocation which points to the target

	 * Each @reloc is a switch table relocation which points to the target

	 * instruction.

	 */

	list_for_each_entry_from(rela, &table->sec->rela_list, list) {

	list_for_each_entry_from(reloc, &table->sec->reloc_list, list) {



		/* Check for the end of the table: */

		if (rela != table && rela->jump_table_start)

		if (reloc != table && reloc->jump_table_start)

			break;



		/* Make sure the table entries are consecutive: */

		if (prev_offset && rela->offset != prev_offset + 8)

		if (prev_offset && reloc->offset != prev_offset + 8)

			break;



		/* Detect function pointers from contiguous objects: */

		if (rela->sym->sec == pfunc->sec &&

		    rela->addend == pfunc->offset)

		if (reloc->sym->sec == pfunc->sec &&

		    reloc->addend == pfunc->offset)

			break;



		dest_insn = find_insn(file, rela->sym->sec, rela->addend);

		dest_insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!dest_insn)

			break;
@@ -1079,7 +1079,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, 


		alt->insn = dest_insn;

		list_add_tail(&alt->list, &insn->alts);

		prev_offset = rela->offset;

		prev_offset = reloc->offset;

	}



	if (!prev_offset) {
@@ -1134,11 +1134,11 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, 
 *

 *    NOTE: RETPOLINE made it harder still to decode dynamic jumps.

 */

static struct rela *find_jump_table(struct objtool_file *file,

static struct reloc *find_jump_table(struct objtool_file *file,

				      struct symbol *func,

				      struct instruction *insn)

{

	struct rela *text_rela, *table_rela;

	struct reloc *text_reloc, *table_reloc;

	struct instruction *dest_insn, *orig_insn = insn;

	struct section *table_sec;

	unsigned long table_offset;
@@ -1163,16 +1163,16 @@ static struct rela *find_jump_table(struct objtool_file *file, 
		    break;



		/* look for a relocation which references .rodata */

		text_rela = find_rela_by_dest_range(file->elf, insn->sec,

		text_reloc = find_reloc_by_dest_range(file->elf, insn->sec,

						    insn->offset, insn->len);

		if (!text_rela || text_rela->sym->type != STT_SECTION ||

		    !text_rela->sym->sec->rodata)

		if (!text_reloc || text_reloc->sym->type != STT_SECTION ||

		    !text_reloc->sym->sec->rodata)

			continue;



		table_offset = text_rela->addend;

		table_sec = text_rela->sym->sec;

		table_offset = text_reloc->addend;

		table_sec = text_reloc->sym->sec;



		if (text_rela->type == R_X86_64_PC32)

		if (text_reloc->type == R_X86_64_PC32)

			table_offset += 4;



		/*
@@ -1189,14 +1189,14 @@ static struct rela *find_jump_table(struct objtool_file *file, 
			continue;



		/*

		 * Each table entry has a rela associated with it.  The rela

		 * Each table entry has a reloc associated with it.  The reloc

		 * should reference text in the same function as the original

		 * instruction.

		 */

		table_rela = find_rela_by_dest(file->elf, table_sec, table_offset);

		if (!table_rela)

		table_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);

		if (!table_reloc)

			continue;

		dest_insn = find_insn(file, table_rela->sym->sec, table_rela->addend);

		dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend);

		if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func)

			continue;
@@ -1205,10 +1205,10 @@ static struct rela *find_jump_table(struct objtool_file *file, 
		 * indicates a rare GCC quirk/bug which can leave dead code

		 * behind.

		 */

		if (text_rela->type == R_X86_64_PC32)

		if (text_reloc->type == R_X86_64_PC32)

			file->ignore_unreachables = true;



		return table_rela;

		return table_reloc;

	}



	return NULL;
@@ -1222,7 +1222,7 @@ static void mark_func_jump_tables(struct objtool_file *file, 
				    struct symbol *func)

{

	struct instruction *insn, *last = NULL;

	struct rela *rela;

	struct reloc *reloc;



	func_for_each_insn(file, func, insn) {

		if (!last)
@@ -1245,10 +1245,10 @@ static void mark_func_jump_tables(struct objtool_file *file, 
		if (insn->type != INSN_JUMP_DYNAMIC)

			continue;



		rela = find_jump_table(file, func, insn);

		if (rela) {

			rela->jump_table_start = true;

			insn->jump_table = rela;

		reloc = find_jump_table(file, func, insn);

		if (reloc) {

			reloc->jump_table_start = true;

			insn->jump_table = reloc;

		}

	}

}
@@ -1302,8 +1302,8 @@ static int add_jump_table_alts(struct objtool_file *file) 


static int read_unwind_hints(struct objtool_file *file)

{

	struct section *sec, *relasec;

	struct rela *rela;

	struct section *sec, *relocsec;

	struct reloc *reloc;

	struct unwind_hint *hint;

	struct instruction *insn;

	struct cfi_reg *cfa;
@@ -1313,8 +1313,8 @@ static int read_unwind_hints(struct objtool_file *file) 
	if (!sec)

		return 0;



	relasec = sec->rela;

	if (!relasec) {

	relocsec = sec->reloc;

	if (!relocsec) {

		WARN("missing .rela.discard.unwind_hints section");

		return -1;

	}
@@ -1329,13 +1329,13 @@ static int read_unwind_hints(struct objtool_file *file) 
	for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) {

		hint = (struct unwind_hint *)sec->data->d_buf + i;



		rela = find_rela_by_dest(file->elf, sec, i * sizeof(*hint));

		if (!rela) {

			WARN("can't find rela for unwind_hints[%d]", i);

		reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));

		if (!reloc) {

			WARN("can't find reloc for unwind_hints[%d]", i);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("can't find insn for unwind_hints[%d]", i);

			return -1;
@@ -1393,19 +1393,19 @@ static int read_retpoline_hints(struct objtool_file *file) 
{

	struct section *sec;

	struct instruction *insn;

	struct rela *rela;

	struct reloc *reloc;



	sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe");

	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("bad .discard.retpoline_safe entry");

			return -1;
@@ -1428,19 +1428,19 @@ static int read_instr_hints(struct objtool_file *file) 
{

	struct section *sec;

	struct instruction *insn;

	struct rela *rela;

	struct reloc *reloc;



	sec = find_section_by_name(file->elf, ".rela.discard.instr_end");

	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("bad .discard.instr_end entry");

			return -1;
@@ -1453,13 +1453,13 @@ static int read_instr_hints(struct objtool_file *file) 
	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

		if (rela->sym->type != STT_SECTION) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s", sec->name);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("bad .discard.instr_begin entry");

			return -1;
@@ -1475,22 +1475,22 @@ static int read_intra_function_calls(struct objtool_file *file) 
{

	struct instruction *insn;

	struct section *sec;

	struct rela *rela;

	struct reloc *reloc;



	sec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls");

	if (!sec)

		return 0;



	list_for_each_entry(rela, &sec->rela_list, list) {

	list_for_each_entry(reloc, &sec->reloc_list, list) {

		unsigned long dest_off;



		if (rela->sym->type != STT_SECTION) {

		if (reloc->sym->type != STT_SECTION) {

			WARN("unexpected relocation symbol type in %s",

			     sec->name);

			return -1;

		}



		insn = find_insn(file, rela->sym->sec, rela->addend);

		insn = find_insn(file, reloc->sym->sec, reloc->addend);

		if (!insn) {

			WARN("bad .discard.intra_function_call entry");

			return -1;

tools/objtool/check.h

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ struct instruction { 
	struct symbol *call_dest;

	struct instruction *jump_dest;

	struct instruction *first_jump_src;

	struct rela *jump_table;

	struct reloc *jump_table;

	struct list_head alts;

	struct symbol *func;

	struct list_head stack_ops;

tools/objtool/elf.c

+218 −90

File changed.

Preview size limit exceeded, changes collapsed.

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